Embodiments of the present invention relate generally to methods and systems for remote sensing and more particularly to remote sensing and/or monitoring utilizing a sensing device, such as may be implemented in a patch that can be placed on or affixed to a subject, where the sensing device includes multiple sensors.
A variety of different remote sensors are used in a wide range of applications such as manufacturing, transportation, facilities management, security, health care, etc. For example, in a health care setting, remote sensors are commonly used for measuring bodily parameters of a patient such as heart rate, blood pressure, blood oxygen level, respiration rate, and core temperature. Many of these sensors are applied externally to the patient's skin.
Previous methods and systems for determining a patient's core temperature from a measurement at the skin assume to calculate an accurate core temperature when a single sensor on a patient's skin is well insulated from the ambient temperature. Other previous methods assume to calculate an accurate core temperature by having a first sensor directly on the skin and a second sensor on the upper surface of a patch, and by heating the upper sensor until it has a temperature equal to the skin sensor, and assuming that this temperature equals core temperature. Another previous method assumes to calculate an accurate core temperature by having a first sensor directly on the skin and a second sensor on the upper surface of a patch and then by using an algorithm that calculates the core temperature based on the difference in the temperature between the two sensors.
These previous methods that use skin surface temperature and ambient temperature need to use algorithms that assume the temperature gradient from a human's core to their skin is identical. This assumption of identical temperature gradient through the body mass will introduce errors in the reported core temperature due to the variation of size, weight, and body type of different people. Furthermore, human temperature measurement done by an electronic patch applied to the skin can be in error when a temperature measuring component is at a different temperature than the skin due to poor thermal contact or due to a gradient across the patch caused by ambient temperature.
In other applications and with other types of sensors, similar problems can affect the measurements made by the sensor. That is, when utilizing an externally applied sensor for measuring a metric, a variety of ambient influences can adversely affect the accuracy and/or reliability of the sensor. Hence, there is a need for improved methods and systems for remote sensing and/or monitoring utilizing a sensing device.